Thanks- I've had a lousy few days (just saw my truck leave on a flatbed), almost no sleep last night, and a very, very long day at work, and, not complaining, but I was in no mood for a research project tonight. I appreciate your looking into it.

Esbit tablets have been around since WWII, and probably the primary use for decades now, at least in the US, is for powering model steam engines (or Stirling engines, in my case). In that context Esbit has made a point of assuring parents that they were non-toxic for a very long time. Clearly they have some stake in that claim.